The present invention is related to a pull cord control device for Venetian blind, including a mounting body made up of an engagement piece extending at one side thereof, and a limiting piece disposed at the other side thereof wherein a U-shaped groove is vertically indented at the inner side of the limiting piece therein for a U-shaped and metallic protection rod to be located therein and abutted against the upper edge of a confinement space defined by a pair of teeth racks symmetrically extending at the limiting piece thereon. A decoration lid of an oval shape with a pull-cord passage slot disposed thereon is integrally formed at one end of the limiting piece thereof with the protection rod exposed precisely at the inner lower edge of the pull-cord passage slot thereof, whereby, a pull cord guided through the upper edge of the protection rod before suspended downwards through the pull-cord passage slot of the decoration lid is refrained from directly rubbing against the frame edges of the pull cord passage slot when drawn to any sides therein to fold/unfold the Venetian blind thereof, and facilitating a smooth operation of the pull cord to achieve the best using condition thereof
Please refer to FIGS. 1 to 2 inclusive. A conventional pull cord control device for Venetian blind includes a mounting body 10 having a pair of positioning stop blocks of half-oval shape 11 symmetrically extending at both sides thereof. A triangular wing 111 is protruding at the outer side of each positioning stop block 11 thereof, and a U-shaped engaging groove 112 is indented at the inner side of the positioning stop blocks 11 thereof for retaining a division rod 20 therein. The mounting body 10 is also equipped with a limiting piece 12 having a pair of teeth racks 121 symmetrically tilted thereon in mesh with a control gear 122 disposed at one side thereof to define a confinement space 14 there-between for a coupling post 13 with an embossed roller 131 mounted thereto to be located in the middle thereof At the other side of the mounting body 10 thereof is disposed an engagement piece 15 having a pair of symmetrical registration posts 151 properly protruding thereon for positioning rollers 152 to be engaged therewith respectively, and a pair of abutting blocks 153 extending downwards at one side thereof A cover 30 having a plurality of coupling holes 31 distributed thereon to be registered with the coupling post 13 and the registration posts 151 of the mounting body 10 respectively is provided with a lid 32 of an oval shape extending at one end thereon to be abutted against the positioning stop blocks 11 of the mounting body 10 thereby. A pull-cord passage slot 321 is disposed at the center of the lid 32 thereof, and a pair of resilient hooks 33 is symmetrically tilted outwards at both outer lateral edges of the cover 30 thereof. In assembly, both ends of a pull cord 40′ extended by one of the positioning roller 152 and led through the space defined by the embossed roller 131 and the control gear 122 thereof are individually passed through the upper and lower sides of the division rod 20 separately before suspending downwards through the pull-cord passage slot 311 thereof The engagement piece 15 of the mounting body 10 is then led through a locating through hole 41 of an upper beam 40 till the resilient hooks 33 and the triangular wings 111 thereof are respectively stopped at both inner lateral sides of the locating through hole 41 thereof. Meanwhile, the abutting blocks 153 of the engagement piece 15 thereof are retained in place by a stop facet 42 extending at one side of the upper beam 40 thereof to locate the pull cord control device thereof at the upper beam 40 therein for the operation of the pull cord 40′ thereof.
There are some drawbacks to such conventional pull cord control device for Venetian blinds. First, both ends of the pull cord 40′ are separately led through the upper and lower sides of the division rod 20 respectively before suspending downwards through the pull-cord passage slot 321 as shown in FIG. 3. In case the pull cord 40′ is randomly drawn to any sides at the pull cord passage slot 321 therein to fold or unfold the Venetian blind thereof, the pull cord 40′ tends to rub directly against the frame edges of the pull cord passage slot 321 thereof in the operation thereof. Under frequent friction thereof, the pull-cord passage slot 321 is easily worn off with rugged frame edges produced thereby, which can inconveniently jam and block the pull cord 40′ in operation thereof. Second, when the cover 30 is assembled onto the mounting body 10 thereof, the lid 32 of the cover 30 is abutted against the outer surface of the positioning stop blocks 11 thereof, which inevitably increases the distance between the resilient hooks 33 and the lid 32 thereof. Thus, the control device thereof mounted to the locating through hole 41 of the upper beam 40 is evidently protruded outside the upper beam 40 in assembly, destroying the overall beauty of the upper beam 40 in appearance.